Characterization of surfactant liquid crystal phases suitable for molecular alignment and measurement of dipolar couplings

Media employed for imparting partial alignment onto solute molecules have r ecently attracted considerable attention, since they permit the measurement of NMR parameters for solute biomolecules commonly associated with solid s tate NMR. Here we characterize a medium which is based on a quasi-ternary s urfactant system comprising cetylpyridinium bromide/hexanol/sodium bromide. We demonstrate that dilute solutions of this system can exist in liquid cr ystalline phases which orient in the magnetic field and allow the measureme nt of residual dipolar couplings under a variety of conditions. The present system is extremely versatile and robust, tolerating different buffer cond itions, temperature ranges and concentrations.